One would hope that premarital sex was rare in Greeley, Colorado, in early 1900s, as one resident learned during that era that her intended was also her immediate relative. From the February 24, 1914 New York Times:

“Greeley, Col.–Just as they were leaving to procure a marriage license and have the nuptial knot tied by a Justice of the Peace. Miss Mary Hardy, a homesteader near Buckingham, Weld County, discovered that Frank Cameron, a neighboring homesteader, to whom she was engaged, was her brother. Miss Hardy fainted, and it was some time before she could be revived.

The discovery of the relationship between Miss Hardy and Cameron, the real name of both being Howard, was brought about through Cameron wearing for the first time in her presence a small gold ring with a peculiar button setting as a fob for his watch chain.

‘Where did you get that ring?’ faltered Miss Hardy, as she noticed and then inspected it.

‘My sister gave me that to remember her by the last time I saw her twenty-three years ago,’ answered Cameron, astonished at her agitation.

‘Then you are my brother!’ exclaimed Miss Hardy and fainted.

When Miss Hardy was revived she proved their relationship beyond all doubt by going to her jewel box and taking from it a silver coin bearing the date of her brother’s birth and his initials, which he had engraved when a boy.

It appears that the brother and sister were deserted in childhood by their parents and later were adopted in different families.”